Dilly Bean Potato Salad

Name: Dilly Bean Potato Salad
Ingredients: 2 shallots, halved lengthwise, very thinly sliced (about 1 cup); 6 tablespoons (or more) red wine vinegar; Kosher salt; 3 pounds baby Yukon Gold potatoes; Freshly ground black pepper; 1 cup (or more) mayonnaise; 1 large pinch of smoked paprika; 3 cups trimmed watercress, purslane, or wild arugula, coarsely chopped; 1 cup Dilly Beans (click for recipe), cut crosswise into 2-inch pieces; 2-3 large hard-boiled eggs, peeled, quartered; 3/4 cup coarsely chopped fresh flat-leaf parsley or celery leaves